JP2007154097A - Carbon black dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the viscosity of a small-sized carbon black dispersion. <P>SOLUTION: The carbon black dispersion contains dry-pulverized carbon black. The carbon black consists of two kinds different in the average primary particle size. The size of the larger particle sized-carbon black is 20-40 nm. That of the smaller-sized one is less than 10-20 nm. The difference in the average primary particle size between the larger particle-sized carbon black and the smaller particle-sized carbon black is not less than 5 nm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a carbon black dispersion that is suitably used for forming a black matrix of a color filter and for inkjet.

  As a means for improving the OD value, which is the optical density of the black matrix for color filters, and the color density of inkjet ink, there is a technique of blending carbon blacks having different particle diameters (Patent Document 1). There was a problem of being expensive.

  Further, in the black matrix for color filters, the black matrix is extremely thinned from the viewpoint of high definition of the LCD screen. In this process, carbon black with a small particle size having an average primary particle size of less than 40 nm is used to improve fine line pattern formation, but the viscosity of such a small particle size carbon black dispersion tends to increase. was there.

The use of such a high-viscosity dispersion in a black matrix for a color filter or an ink-jet ink has been impractical in its characteristics and is not practical.
Japanese Patent Laid-Open No. 9-133806

  The problem to be solved by the present invention is to reduce the viscosity of the carbon black dispersion.

  As means for solving the above problems, the present inventors have made various studies and found a method for suppressing the increase in the viscosity of the carbon black dispersion.

That is, the present inventors have found that a dispersion using carbon black that has been dry pulverized as a raw material has a lower viscosity than a dispersion using carbon black that has not been dry pulverized as a raw material.
Furthermore, a dispersion using a carbon black treated product obtained by dry pulverization of two or more types of carbon black having different average primary particle sizes as a raw material is a dispersion using a carbon black mixture that was not dry pulverized in the same combination. The knowledge which becomes a viscosity lower than a liquid was also obtained.

That is, the present invention
(1) A carbon black dispersion containing dry-pulverized carbon black.
(2) The carbon black dispersion according to (1), wherein the carbon black is composed of two or more kinds having different average particle sizes, the large particle size carbon black is 20 to 40 nm, and the small particle size carbon black is less than 8 to 20 nm. .
(3) The carbon black dispersion according to (1) or (2), wherein the difference in average primary particle size between the large particle size carbon black and the small particle size carbon black is 5 nm or more.
(4) The carbon black dispersion according to any one of (1) to (3), wherein the compounding ratio of the small particle size carbon black to the large particle size carbon black is 1/3 to 1/20.
(5) A method for producing a carbon black dispersion in which two or more carbon blacks having different average primary particle diameters are mixed and then dry pulverized.
(6) A method for producing a carbon black dispersion in which two or more carbon blacks having different average primary particle diameters and a pigment derivative are mixed and then dry pulverized.
(7) A method for reducing the viscosity of a carbon black dispersion using dry-pulverized carbon black.
It is.

Since the carbon black dispersion of the present invention contains dry-pulverized carbon black, the carbon black dispersion is good and the viscosity is low.
Moreover, since carbon black consists of 2 or more types from which an average particle diameter differs, large particle size carbon black is 20-40 nm, and small particle size carbon black is less than 8-20 nm, Therefore Color density and optical density are high, A viscosity is low .
Since the difference in average primary particle size between the large particle size carbon black and the small particle size carbon black is 5 nm or more, the coloring density and the optical density are higher and the viscosity is lower.
Moreover, since the compounding ratio of the small particle size carbon black to the large particle size carbon black is 1/3 to 1/20, the carbon black is further dispersed and the viscosity is low.

In the method for producing a carbon black dispersion according to the present invention, two or more types of carbon blacks having different average primary particle sizes are mixed and then dry pulverized, so that the production efficiency is good and the resulting carbon black dispersion is colored. High density and optical density, low viscosity.
Furthermore, in the method for producing a carbon black dispersion of the present invention, since two or more types of carbon blacks having different average primary particle sizes and a pigment derivative are mixed and then dry pulverized, the dispersion is very good. Therefore, the carbon black dispersion obtained by using this has a high coloring density and optical density and a low viscosity.

<Carbon black treated product>
In the present invention, as a means for realizing a low-viscosity dispersion, first, carbon black is dry-pulverized to obtain a carbon black treated product.
The average primary particle size of the carbon black used in the present invention is preferably 40 nm or less. The average primary particle diameter of carbon black in the present invention is a value measured with an electron microscope.

  Further, the DBP absorption amount, which is a representative characteristic of carbon black, is not particularly limited, but generally 40 to 120 ml / 100 g is preferable. 40-100 ml / 100g is still more preferable.

  The carbon black used in the present invention may be one type, but it is preferable to use two or more types having different average primary particle sizes. At this time, it is preferable to use one or more kinds of carbon black having a large particle diameter (hereinafter also referred to as parent carbon black) and carbon black having a smaller average primary particle diameter (small carbon black).

  When two or more types of carbon black having different average primary particle sizes are used, the average primary particle size of the large particle size carbon black as the base is 20 to 40 nm, and the average primary particle size of the other small particle size carbon blacks is 8 A combination of less than ˜20 nm is preferred. A combination having a large particle size of 20 to 30 nm and a small particle size of less than 8 to 20 nm is more preferable.

  The increase in color density and optical density and decrease in viscosity of the carbon black dispersion is due to the particle size of the base carbon black and the degree of structure development (DBP absorption), the composition of the small particle size and its composition ratio, and the dry grinding of the carbon black. Affects. From the viewpoint of increasing the optical density of the carbon black dispersion due to the fine packing, the difference in average primary particle size between the large particle size carbon black as the base and the other small particle size carbon black is preferably 5 nm or more, and preferably 10 nm or more. Is more preferable.

  Further, the compounding ratio of the small particle size carbon black used with respect to the large particle size carbon black as a base is preferably 1/3 to 1/20. More preferably, it is 1/3 to 1/10. When using 2 or more types of small particle size carbon black, the compounding ratio between small particle sizes is not specifically limited.

  Examples of the dry pulverization include an apparatus that uses a medium such as an attritor, a ball mill, and a vibration mill, and an apparatus that does not use a medium such as a pin mill, hammer mill, and micros. Moreover, the temperature at the time of dry pulverization is not particularly limited, but 60 to 110 ° C. is preferable from the viewpoint of safety during operation.

When two or more types of carbon black are used, each carbon black can be dry pulverized and then mixed to produce a carbon black treated product.
Moreover, each carbon black can be mixed in advance and then dry pulverized to produce a carbon black treated product. The method of producing a carbon black dispersion using the carbon black treated product obtained by this method is more preferable from the viewpoint of not only the production efficiency but also the viscosity of the carbon black dispersion can be further reduced.

Carbon black can be dry pulverized in the presence of a pigment derivative. In this case, the pigment derivative can be added before dry pulverization of carbon black or during dry pulverization, or when two or more carbon blacks are used, when mixing each carbon black.
The presence of the pigment derivative in the carbon black dry pulverization step further improves the dispersion of the carbon black. In particular, when two or more types of carbon black are used, the viscosity can be further reduced.

  When mix | blending a pigment derivative, the compounding quantity of pigment derivative 0.1-30 weight part is preferable with respect to 100 weight part of carbon black, and 0.5-20 weight part is more preferable. When the content of the pigment derivative is less than 0.1 parts by weight, the effect of dispersing the carbon black may not be sufficiently exerted, and when more than 30 parts by weight, the dispersion of the carbon black may become unstable. is there.

（式中、Ｑは有機色素残基、Ｘは直接結合、−ＣＯＮＨ−Ｙ_２−、−ＳＯ_２ＮＨ−Ｙ_２−、または−ＣＨ_２ＮＨＣＯＣＨ_２ＮＨ−Ｙ_２−（但し、Ｙ_２は置換基を有してもよいアルキレン基またはアリール基を表す。）、Ｙ_１は−ＮＨ−または−Ｏ−、Ｚは水酸基、アルコキシ基、下記一般式（Ｂ）で示される置換基、またはｎが１の場合には−ＮＨ−Ｘ−Ｑ、、Ｒ_１およびＲ_２は、それぞれ独立に置換もしくは無置換のアルキル基、またはＲ_１とＲ_２とで形成される少なくとも窒素原子を含むヘテロ環、ｍは１から６の整数、ｎは１から４の整数を表す。）
一般式（Ｂ）

（式中、Ｙ_３は−ＮＨ−または−Ｏ−を表す。また、ｍ、Ｒ_１、Ｒ_２は一般式（Ａ）で定義したとおりである。） The dye derivative used in the present invention is not particularly limited, and any dye derivative can be used as long as it can be applied to a black matrix for ink-jet and color filters. A compound in which a substituent is introduced into an organic dye is preferable. As the pigment derivative, those represented by the following general formula (A) are preferably used.
Formula (A)

(Wherein Q is an organic dye residue, X is a direct bond, —CONH—Y ₂ —, —SO ₂ NH—Y ₂ —, or —CH ₂ NHCOCH ₂ NH—Y ₂ — (where Y ₂ is a substituent) Represents an alkylene group or an aryl group which may have a group), Y ₁ represents —NH— or —O—, Z represents a hydroxyl group, an alkoxy group, a substituent represented by the following general formula (B), or n represents In the case of 1, —NH—XQ, R ₁ and R ₂ are each independently a substituted or unsubstituted alkyl group, or a heterocycle containing at least a nitrogen atom formed by R ₁ and R ₂ , m represents an integer of 1 to 6, and n represents an integer of 1 to 4.)
General formula (B)

(Wherein Y ₃ represents —NH— or —O—, and m, R ₁ and R ₂ are as defined in formula (A).)

Examples of the dye derivative represented by the general formula (A) include dye derivatives represented by the following general formulas (1) to (10).

  Examples of the organic dye constituting the dye derivative represented by the general formula (A) include phthalocyanine, quinacridone, quinacridonequinone, isoindolinone, quinophthalone, diketopyrrolopyrrole, perylene, perinone, Indigo, thioindigo, dioxazine, anthraquinone, pyranthrone, anthanthrone, flavanthrone, indanthrone, metal complex, etc. condensed polycyclic organic pigments, benzimidazolone, insoluble azo, condensation Other organic pigments or dyes such as azo-based and soluble azo-based are listed.

In the present invention, light yellow aromatic polycyclic compounds such as naphthalene series and anthraquinone series, which are not generally called dyes, are also treated as organic dyes.
These organic dyes may be used alone or in combination of two or more.

<Carbon black dispersion>
The carbon black dispersion of the present invention is obtained by mixing and dispersing a carbon black treated product obtained by dry pulverizing carbon black, a resin, a pigment derivative and a solvent.
The resin, the pigment derivative and the solvent used in the present invention are not particularly limited and may be any as long as they can be applied to a black matrix for ink jet or color filters.

  In the case of a carbon black treated product in which a pigment derivative is already blended, the pigment derivative may be blended again or not in this dispersion step.

  When the pigment derivative is blended again, those exemplified in the carbon black treated product are preferably used. 0.1-30 weight part is preferable and, as for the total compounding quantity of the pigment derivative with respect to 100 weight part of carbon black, 0.5-20 weight part is more preferable. When the total amount of the pigment derivative is less than 0.1 parts by weight, the effect of dispersing the carbon black may not be sufficiently exerted, and when more than 30 parts by weight, the dispersion of the carbon black becomes unstable. There is.

  The resins include butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin, polyester resin, acrylic resin , Alkyd resins, polystyrene, polyamide resins, rubber resins, cyclized rubber resins, celluloses, polyethylene, polybutadiene, polyimide resins and other thermoplastic resins, epoxy resins, benzoguanamine resins, rosin modified maleic resins, rosin modified fumaric resins , Melamine resin, urea resin, phenol resin and the like. Two or more kinds of resins can be used in combination depending on the application.

  Examples of the solvent include cyclohexanone, ethyl cellosolve acetate, butyl cellosolve acetate, 1-methoxy-2-propyl acetate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, ethylbenzene, ethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, xylene, ethyl cellosolve, methyl- Examples include n-amyl ketone, propylene glycol monomethyl ether, toluene, methyl ethyl ketone, ethyl acetate, methanol, ethanol, isopropyl alcohol, butanol, isobutyl ketone, and petroleum solvents. These can be used alone or in combination.

  The distribution means may be media distribution or media-less distribution. For media dispersion, generally, ceramic beads such as glass and zirconia are introduced into a dispersing machine such as a bead mill, an attritor, a ball mill, and a paint conditioner, and dispersed together with carbon black. Furthermore, you may combine with medialess dispersers, such as 3 rolls, a high-pressure homogenizer, a jet mill, a micros, and an ultrasonic disperser.

  In addition, when dispersion | distribution is inadequate and there exists a coarse particle size, you may remove them by filtration. Even if the dispersion is sufficient, it is desirable to perform filtration for the purpose of removing foreign substances in the system. Moreover, there is no limitation in particular in the kind of filter.

  As described above, the carbon black dispersion of the present invention can be produced. The carbon black dispersion of the present invention is preferably used for forming a black matrix for a color filter and for inkjet applications.

Hereinafter, the present invention will be described in more detail with reference to examples.
“Parts” and “%” indicate “parts by weight” and “% by weight” unless otherwise specified.
(acrylic resin)
800 parts of cyclohexanone was put into a reaction vessel and heated to 100 ° C. while injecting nitrogen gas. At the same temperature, a mixture of the following monomer and thermal polymerization initiator was added dropwise over 1 hour to carry out a polymerization reaction.
60.0 parts of styrene, 60.0 parts of methacrylic acid, 65.0 parts of methyl methacrylate, 65.0 parts of butyl methacrylate, 10.0 parts of azobisisobutyronitrile, and further reacted at 100 ° C. for 3 hours Then, 2.0 parts of azobisisobutyronitrile dissolved in 50 parts of cyclohexanone was added. Furthermore, reaction was continued at 100 degreeC for 1 hour, and the acrylic resin solution was obtained. The weight average molecular weight of the acrylic resin was about 40,000.
After cooling to room temperature, cyclohexanone was added to prepare an acrylic resin solution having a nonvolatile content of 30%.

(Dye derivative)
The following pigment derivatives were used.

[Example 1]
In a dry pulverizer, 75 parts of carbon black having a particle size of 23 nm and a DBP oil absorption of 64 ml / 100 g was dry pulverized for 10 minutes to obtain a carbon black treated product.
24 parts of this treated product, 17 parts of an acrylic resin solution, 1 part of a pigment derivative, and 78 parts of cyclohexanone are mixed, and the whole amount of the mixture is put into a paint conditioner in which 120 parts of zirconia beads having a particle diameter of 0.8 mm are put, Dispersion was carried out for 5 hours to obtain a carbon black dispersion.

[Example 2]
60 parts of carbon black having a particle diameter of 23 nm and DBP oil absorption of 64 ml / 100 g were mixed with 15 parts of carbon black having a particle diameter of 15 nm and DBP oil absorption of 52 ml / 100 g.
The mixture was dry pulverized for 10 minutes with a dry pulverizer to obtain a carbon black treated product. This treated product was dispersed in the same manner as in Example 1 to obtain a carbon black dispersion.

[Example 3]
60 parts of carbon black having a particle diameter of 34 nm and DBP oil absorption of 48 ml / 100 g were mixed with 15 parts of carbon black having a particle diameter of 14 nm and DBP oil absorption of 50 ml / 100 g.
The mixture was dry pulverized for 10 minutes with a dry pulverizer to obtain a carbon black treated product. This treated product was dispersed in the same manner as in Example 1 to obtain a carbon black dispersion.

[Example 4]
60 parts of carbon black having a particle diameter of 34 nm and DBP oil absorption of 48 ml / 100 g were mixed with 15 parts of carbon black having a particle diameter of 14 nm and DBP oil absorption of 50 ml / 100 g.
The mixture was dry pulverized for 10 minutes with a dry pulverizer to obtain a carbon black treated product. This treatment was repeated 5 times to obtain 375 parts of a carbon black treated product. 320 parts of this treated product, 224 parts of an acrylic resin solution, 13 parts of a pigment derivative, and 443 parts of cyclohexanone are mixed, and the total amount of the mixture is DISPERMAT SL-0251C1-EX charged with 720 parts of zirconia beads having a particle diameter of 0.5 mm. Circulating dispersion was performed for 105 minutes (manufactured by Eiko Seiki Co., Ltd.) to obtain a carbon black dispersion. The integrated power required for this dispersion was 1200 Wh.

[Example 5]
60 parts of carbon black having a particle diameter of 34 nm and DBP oil absorption of 48 ml / 100 g, 15 parts of carbon black having a particle diameter of 14 nm and DBP oil absorption of 50 ml / 100 g, and 3 parts of a pigment derivative were mixed. The mixture was dry pulverized for 10 minutes with a dry pulverizer to obtain a carbon black treated product. This treatment was repeated 5 times to obtain 390 parts of a carbon black treated product.
333 parts of this treated product, 224 parts of an acrylic resin solution, and 443 parts of cyclohexanone were mixed, and the total amount of the mixture was DISPERMAT SL-0251C1-EX (produced by Eiko Seiki Co., Ltd.) charged with 720 parts of zirconia beads having a particle size of 0.5 mm. ) For 150 minutes to obtain a carbon black dispersion. The integrated power required for this dispersion was 1200 Wh.

[Comparative Example 1]
24 parts of carbon black having a particle size of 23 nm and a DBP oil absorption of 64 ml / 100 g, 17 parts of an acrylic resin solution, 1 part of a pigment derivative and 78 parts of cyclohexanone were mixed.
The total amount of this mixture was charged into a wet attritor into which 120 parts of zirconia beads having a particle diameter of 0.8 mm were charged, and dispersed for 5 hours to obtain a carbon black dispersion.

[Comparative Example 2]
60 parts of carbon black having a particle diameter of 34 nm and DBP oil absorption of 48 ml / 100 g were mixed with 15 parts of carbon black having a particle diameter of 14 nm and DBP oil absorption of 50 ml / 100 g.
24 parts of this mixture, 17 parts of an acrylic resin solution, 1 part of a pigment derivative, and 78 parts of cyclohexanone were mixed.
The total amount of this mixture was charged into a paint conditioner charged with 120 parts of zirconia beads having a particle size of 0.8 mm and dispersed for 5 hours to obtain a carbon black dispersion.

[Comparative Example 3]
Mix 256 parts of carbon black with a particle diameter of 34 nm and DBP oil absorption of 48 ml / 100 g, 64 parts of carbon black with a particle diameter of 14 nm and DBP oil absorption of 50 ml / 100 g, 224 parts of an acrylic resin solution, 13 parts of a pigment derivative, and 443 parts of cyclohexanone. The total amount of the mixture was circulated and dispersed for 135 minutes using DISPERMAT SL-0251C1-EX (manufactured by Eihiro Seiki Co., Ltd.) into which 720 parts of zirconia beads having a particle diameter of 0.5 mm were charged, to obtain a carbon black dispersion. The integrated power required for this dispersion was 1200 Wh.

(Viscosity measurement)
The carbon black dispersions in Examples 1 and 2 and Comparative Example 1 were measured for viscosity at 25 ° C. and 50 rpm using an EM viscometer (manufactured by TOKIMEC).
The carbon black dispersions in Example 3 and Comparative Example 2 were measured for viscosity at 25 ° C. and 20 rpm using a TVE-20L viscometer (manufactured by Toki Sangyo Co., Ltd.).
The carbon black dispersions in Examples 4 and 5 and Comparative Example 3 were measured for viscosity at 25 ° C. using a viscoelasticity measuring device (manufactured by TA Instruments Japan).

(OD value measurement)
A carbon black dispersion diluted with cyclohexanone so as to have a solid content concentration of 20% was applied to a glass substrate with a spin coater and heated at 140 ° C. for 2 minutes.
The OD value of the coated substrate was measured with a Macbeth densitometer (GRETAG D200-II) to determine the optical density (OD value) at a film thickness of 1.0 μm.

Claims (7)

  A carbon black dispersion containing dry pulverized carbon black.   The carbon black dispersion liquid according to claim 1, wherein the carbon black is composed of two or more kinds having different average primary particle diameters, the carbon black having a large particle diameter is 20 to 40 nm, and the carbon black having a small particle diameter is less than 8 to 20 nm.   The carbon black dispersion according to claim 1 or 2, wherein a difference in average primary particle size between the large particle size carbon black and the small particle size carbon black is 5 nm or more.   The carbon black dispersion according to any one of claims 1 to 3, wherein the mixing ratio of the small particle size carbon black to the large particle size carbon black is 1/3 to 1/20.   A method for producing a carbon black dispersion in which two or more carbon blacks having different average primary particle sizes are mixed and then dry pulverized.   A method for producing a carbon black dispersion in which two or more carbon blacks having different average primary particle sizes and a pigment derivative are mixed and then dry-pulverized.   A method for reducing the viscosity of a carbon black dispersion using dry-pulverized carbon black.